Safe femoral tunnel drilling angles avoid injury to the medial and posteromedial femoral anatomic structures during single-bundle posterior cruciate ligament reconstruction with the inside-out technique

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA sports traumatology, arthroscopy : official journal of the ESSKA, 2023-08, Vol.31 (8), p.3390-3398
• Main Authors: Guo, Jia, Qi, Chao, Zhang, Dongfang, Yang, Guodong, Wang, Chen, Yang, Pu, Wang, Bin
• Format: Article
• Language: English
• Subjects: Cadavers; Cartilage; Cartilage (articular); Damage; Drilling; Femur; Health risks; Iatrogenesis; Injury prevention; Knee; Ligaments; Medicine; Medicine & Public Health; Orthopedics; Risk; Risk reduction; Sports Medicine; Tunnels
• ISSN: 0942-2056; 1433-7347
• DOI: 10.1007/s00167-023-07412-0

Purpose To investigate the relationship between the medial and posteromedial femoral anatomic structures and the femoral tunnel exit produced by different tunnel orientations when creating the femoral tunnel for posterior cruciate ligament reconstruction (PCLR) using the inside-out (IO) technique and to estimate safe tunnel orientations to minimize the risk of iatrogenic injury to these structures. Methods Eleven cadaveric knees were used. The medial and posteromedial aspects of each knee joint were dissected to reveal the "safe zone," which is a bony area that avoids the distribution or attachment of at-risk structures (MCL, PMC structures, and articular cartilage), while remaining 10 mm away from the articular cartilage. The hypothesis of this study was that by creating the femoral tunnel at specific angles using the IO technique, the tunnel outlet would be as close to the safe zone as possible, protecting the at-risk structures from damage. Femoral tunnels were drilled at 20 different angle combinations on each specimen: 0°, 15°, 30°, 45°, and 60° relative to a line parallel to the transepicondylar axis in the axial plane, as well as 15°, 30°, 45°, and 60° relative to a line parallel to the femoral axis in the coronal plane. The positional relationship between each tunnel exit and the safe zone was recorded, and the shortest distance between the exit center and the safe zone boundary was measured. Results The risk of iatrogenic injury differed depending on the drilling orientation ( χ 2  = 168.880, P